The present invention relates to a metal/semiconductor junction Schottky diode optical device using a distortion grown layer, and more particularly to an optical device using a multiple quantum well structure having an electro-optical absorption effect in a compound semiconductor as an intermediate layer of a metal/semiconductor junction Schottky diode.
Generally, optical devices using a heterogeneous junction compound semiconductor, especially devices using a nonlinear electro-optical absorption effect, are important devices in optical exchange and communication systems which process an optical signal in the vertical direction of the devices, and as a result, have advantages such as parallel processing of the optical signal, high integration of the devices, etc.
An optical device such as self electro-optical effect device having a multiple quantum well structure in intermediate layer of a conventional pin diode is able to produce optical bistable characteristics used for an optical logic function if a symmetrical structure is present having a negative resistance characteristic of the diode. The speed and signal processing performance of an optical device, with the pin diode structure, having electronic device properties involving charge/discharge of optical current caused by a light signal is mainly determined by the light intensity of an operating signal. Therefore, the device is greatly influenced by an absorption saturation effect and a thermal effect when a strong light intensity is required for high-speed signal processing. In particularly, a device having optical bistable characteristics has a deterioration in performance caused by the thermal effect.
In a pin diode structure receiving the light signal from the upper portion of a diode layer grown on a thick substrate, it is difficult to overcome the thermal deterioration of the device performance caused by a temperature rise. A thermal cancellation layer is required having an excellent thermal conductivity at a small distance (within a few .mu.m) from a thermal source in order to cancel the local thermal effects on an active layer of an intermediate portion of the diode. In the conventional pin structure, since the thickness of a upper electrode layer and a mirror layer is limited and an upper layer of the structure should be open to the reception of a signal light, effective thermal cancellation is difficult. To solve this problem, a device structure for canceling a localized thermal rise generated from the device is required. However, in the device having the conventional pin diode GaAs/Al.sub.x Ga.sub.1-x As structure, since a thermal cancellation layer is applied with respect to a local thermal source, a serious problem arises in a manufacturing process.